Imagine two restaurants, one at each end of a block. One is a famous four-star establishment, known for its fine cuisine; the other is a McDonald's, popular for its low prices and speedy service. If the élite restaurant opens a branch on every nearby block, it will lose its cachet as well as its customers. Likewise, if the McD's starts serving pricey, five-course meals, its fans will take a hike. That's the central notion of this illuminating book. Maney, a veteran business journalist, calls this dichotomy...